Statistics hw help ASAP plz

Answer the following questions regarding confidence intervals.
All confidence intervals contain three major components:
a. Estimate
b. Critical Value
c. SE of Estimate
Identify the general form of a confidence interval.
a +/- b*c
a +/- b*sqrt(c)
a +/- sqrt(b)*c
a +/- sqrt(b*c)
a +/- (b+c)
Several years ago, adult tiger sharks found in the Hawaiian islands were known to have a mean length of 8.00 feet. A biologist is concerned that changes to the habitats for tiger sharks near the islands have changed drastically in the last few years due to tourism, and that this may be causing them to be grow differently. She captures a sample of 21 adult tiger sharks, measures their length, and then returns them to the ocean. Those 21 sharks have an average length of 12, with a standard deviation of 4. Is there evidence that indicates the adult tiger sharks' lengths have changed? Construct a confidence interval to help the biologist answer this question.
What are the degrees of freedom?
20
21
22
19
41
Find the critical value associated with a 99% confidence interval.
2.5280
2.8314
2.8453
2.8188
2.5176
Calculate the standard error.
4.0000
0.8729
3.4915
0.4364
0.1905
Calculate the margin of error of the sample mean associated with a 99% confidence interval.
0.5420
2.2067
2.4715
11.3812
2.4837
Find a 99% confidence interval for the true value of the mean.
(9.52 , 14.48)
(9.79 , 14.21)
(11.52 , 12.48)
(5.52 , 10.48)
(11.46 , 12.54)
Suppose we want to be 99% confident that the sample mean is within a distance of 1.30 of the true population mean. What is the minimum sample size required to achieve this?
25
63
62
24
21

Solution Preview :
The solution is based on Net Present Value and Cramer’s rule of matrix. Net Present Value (NPV) is the difference between the present value of cash inflows and the present value of cash...